For example, a vehicle-mounted system according to Patent Literature 1 includes a display disposed on a center pad of a steering wheel, a touch panel disposed on the display, and a user interface controller that displays a screen, in which buttons are arranged, on the display and that receives a driver's operation on a button. The user interface controller displays a screen in which buttons are arranged, in the form of an arc of a circle, in each of right and left sides of a display area of the display, thereby enabling the driver to move only the thumb of his or her hand to operate a button without taking either hand holding the steering wheel off the steering wheel. The user interface controller also moves the position of the arc disposed in each of the right and left sides of the display area of the display in accordance with the holding position of the steering wheel, thereby being able to ensure a high degree of ease of use regardless of the driver's driving state.